Zero-Dimensional Graphene and Its Behavior under Mechanochemical Activation with Zinc Ferrite Nanoparticles
Zero-Dimensional Graphene and Its Behavior under Mechanochemical Activation with Zinc Ferrite Nanoparticles
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DOI：
10.1557/adv.2019.400
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发表时间：
2020-07
期刊：
影响因子：
0.8
通讯作者：
M. Sorescu;M. Knauss;Alice Perrin;M. McHenry
中科院分区：
文献类型：
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作者：
M. Sorescu;M. Knauss;Alice Perrin;M. McHenry
将零维石墨烯（SkySpring Nanomaterials，粒径 1–5 nm）和铁酸锌纳米粒子（Alfa Aesar，粒径 50 nm）的等摩尔混合物通过高能球磨进行机械化学活化，时间间隔为 0–12 小时。通过穆斯堡尔谱和磁测量分析了它们的结构和磁性。没有石墨烯研磨的铁酸锌的光谱符合一个四极分裂双峰（四极分裂0.5毫米/秒，异构体位移0.23毫米/秒），表明铁氧体锌具有超顺磁性。双合峰的线宽从 0.41 增加到 0.64 mm/s，这与球磨加工造成的颗粒尺寸减小相关。当石墨烯添加到研磨粉末中时，穆斯堡尔谱显示出现了另一个四极双峰，四极分裂为 0.84 mm/s，异构体位移为 -0.38 mm/s。当研磨时间增加时，其在光谱中的丰度保持恒定为 4.48%。第二个双峰可能与占据铁原子附近的碳原子有关。在 5 K 温度下，在 5 T 的外加磁场中记录磁滞回线。观察到磁滞回线接近饱和的变化，用石墨烯研磨 12 小时的样品达到饱和。在 5-300 K 范围内对所有样品进行零场冷却-场冷却 (ZFC-FC)，施加 200 Oe 的磁场。研究发现石墨烯可以将粉末研磨系统的磁性稳定到约 90 K 的阻塞温度。
Equimolar mixtures of zero-dimensional graphene (SkySpring Nanomaterials, 1–5 nm particle size) and zinc ferrite nanoparticles (Alfa Aesar, 50 nm particle size) were exposed to mechanochemical activation by high-energy ball milling for time intervals of 0–12 hours. Their structural and magnetic properties were analyzed by Mössbauer spectroscopy and magnetic measurements. The spectra of zinc ferrite milled without graphene were fitted with one quadrupole-split doublet (quadrupole splitting 0.5 mm/s, isomer shift 0.23 mm/s) and indicated that zinc ferrite was superparamagnetic. The line width of the doublet increased from 0.41 to 0.64 mm/s, which correlates with a reduction in particle size as effect of the ball milling processing performed. When graphene was added to the milling powders, the Mössbauer spectra showed the appearance of another quadrupole doublet, with a quadrupole splitting of 0.84 mm/s and an isomer shift of -0.38 mm/s. Its abundance to the spectrum remained constant to 4.48% while the milling time was increased. This second doublet could be related to carbon atoms occupying neighborhoods in the proximity of iron atoms. Hysteresis loops were recorded in an applied magnetic field of 5 T at a temperature of 5 K. A change in the approach to saturation of the loop was observed, with saturation being achieved for the sample milled for 12 hours with graphene. Zero-field-cooling-field-cooling (ZFC-FC) was performed on all samples between 5–300 K with an applied magnetic field of 200 Oe. Graphene was found to stabilize the magnetic properties of the milled system of powders to a blocking temperature of about 90 K.